Method for degrading (co)polymers in an extruder and extruder for performing the method
a polymer and extruder technology, applied in the direction of mixing, transportation and packaging, rotary stirring mixers, etc., can solve the problems of high safety requirements, high hazard potential, peroxide, etc., and achieve low viscosity and cost-effective
Active Publication Date: 2017-06-20
HENKEL KGAA
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Benefits of technology
The present invention provides a method for producing low-viscosity degraded (co)polymers in a cost-effective and energy-efficient manner while avoiding uncontrolled foaming. The technical effect of the invention is to overcome the limitations of prior art methods.
Problems solved by technology
One disadvantage of the above method has been found to be that high safety requirements need to be met, because a variety of radical formers, such as peroxides, exhibit a high hazard potential.
Furthermore, as peroxides decay, volatile components are released, which can lead to an undesirable foaming of the degraded polymer in the extruder.
In addition, the use of larger amounts of peroxides often leads to inefficiency of the method, because these materials represent a high portion of costs in the total costs of the method.
Due to the difficulty of controlling effective oxygen entry into the polymer melt, the above-mentioned method has problematic reproducibility.
Also, in the exclusive use of oxygen or an oxygen-containing gas, even at very high temperatures, it is not always possible to make the degradation process so effective that polymers with low viscosities are obtained.
Method used
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Embodiment Construction
[0012]The method according to the invention is based on the sequential degradation of (co)polymers in an extruder, wherein the (co)polymer used is degraded by the action of at least one radical former in a first extrusion section, while a further decomposition of the (co)polymer is achieved by means of an oxygen gas in a second extruder section.
[0013]The method according to the invention for degrading (co)polymers in an extruder comprises the following steps:[0014]a) supplying a (co)polymer by means of a charging opening in a first extrusion section of the extruder;[0015]b) degrading the (co)polymer under shear stress in the first extrusion section, in the presence of at least one radical former, in order to produce a first degraded (co)polymer;[0016]c) transferring the first degraded (co)polymer from the first extrusion section into a second extrusion section of the extruder, wherein the first extrusion section is separated from the second extrusion section by a sealing means;[0017...
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Abstract
The invention relates to a method for degrading (co)polymers in an extruder and an extruder suitable for performing said method.
Description
FIELD OF THE INVENTION[0001]The present invention relates to a method for degrading (co)polymers in an extruder, and to an extruder suitable for performing said method.[0002]The degradation of (co)polymers with the aid of extruders is sufficiently known. The action of shear forces at high temperatures makes it possible to selectively reduce or decompose the molecular weight of (co)polymers, due to the resulting thermomechanical stress. A further increase in the efficiency of the decomposition process is possible when said process is carried out in the presence of radical formers, such as, for example, peroxides.BACKGROUND OF THE INVENTION[0003]In this context, patent document DE 4000695 C2 describes, for example, a method for producing substantially amorphous poly-alpha-olefins, which are prepared from higher-molecular-weight amorphous poly-alpha-olefins through shear stress above the softening point, in the presence of a radical former, wherein the melt viscosity of the higher-mole...
Claims
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IPC IPC(8): C08F8/50B01F7/00C08F210/16B29C47/76B29C47/60B29C47/08B29C47/10C08F236/04B29C48/295B29C48/38B29C48/40B29C48/53B29C48/535B29C48/74B29C48/76
CPCC08F236/04B01F7/00416B29C47/0871B29C47/1072B29C47/1081B29C47/6018B29C47/6025B29C47/767C08F8/50C08F210/16C08F8/06C08F10/00B01F2215/0049C08F2810/10B29C48/53B29C48/268B29C48/295B29C48/297B29C48/535B29C48/767B29C48/40Y02W30/62B01F27/1143B01F2101/2805
Inventor KASPER, DIRKBRENGER, ANDREASTHIERBACH, ILJA
Owner HENKEL KGAA